NEW YORK (GenomeWeb News) – A set of loci implicated in increased obesity risk seem to show even stronger ties to body mass index in individuals who regularly indulge in sugary drinks, according to a study online in the New England Journal of Medicine.
Researchers from the Harvard School of Public Health, Brigham and Women's Hospital, and elsewhere assessed both BMI and genetic profiles in more than 11,300 individuals (6,934 women and 4,423 men). Using a genetic predisposition for obesity score based on information at almost three-dozen BMI-associated SNPs, the researchers found that individuals with risk-associated alleles tended to have higher BMIs, both in the discovery group and in tens of thousands of individuals evaluated in the replication group. But the effect was more pronounced in individuals who reported drinking sugar-sweetened drinks regularly, the investigators reported, particularly those downing one or more of these beverages each day.
"Our study … provides reproducible evidence from three prospective cohorts to show genetic and dietary factors — sugar-sweetened beverages — may mutually influence their effects on body weight and obesity risk," Harvard School of Public Health researcher Lu Qi, the study's senior author, said in a statement. "The findings may motivate further research on interactions between genomic variation and environmental factors regarding human health."
In Nature Genetics, an international team led by investigators in the UK reports on findings from a genome-wide association study of breast cancer in men.
The researchers saw six suspicious loci based on their initial discovery GWAS, which involved 823 men with breast cancer and 2,795 unaffected controls genotyped on Illumina arrays. All of these individuals were of European descent and had been enrolled through programs in the UK or the US. Following validation studies in hundreds more cases and controls, the team came up with one SNP that was significantly associated with male breast cancer: a chromosome 14 variant in the RAD51B gene. Another variant that had shown more tenuous ties to the disease in a past study — a SNP in the chromosome 16 gene TOX3 —also showed some association with male breast cancer in the new analysis.
An American team turned to transcriptional profiling in an effort to understand the clinical heterogeneity in multiple sclerosis.
As they report in Science Translational Medicine, the researchers used messenger RNA expression arrays to test peripheral mononuclear cells in blood samples collected from 141 untreated MS patients. Based on the gene expression profiles found in these samples, the investigators defined two subgroups of MS, each with distinct blood cell transcriptional signatures.
These findings were subsequently verified in two more cohorts of individuals with MS who had received either glatiramer acetate- or interferon beta-based treatment for the disease. The team's follow-up experiments hinted that transcriptional differences between the two MS subgroups may relate to inter-individual differences in disease patterns and treatment response. In particular, they found, individuals in one of the expression-defined subsets of MS tended to have higher levels of lymphocyte immune pathway signaling, were more prone to inflammation while receiving MS treatments, and were more likely to relapse.
"Our study is an important step towards the goal of personalized medicine in MS," senior author Philip De Jager, a neuropsychiatric genomics researcher affiliated with Brigham and Women's Hospital, Harvard Medical School, and the Broad Institute, said in a statement, "but much work remains to be done to understand under which circumstance and in combination with which other information this transcriptional signature may become useful in a clinical setting."
Researchers from BGI-Shenzhen, the University of Copenhagen, and elsewhere have identified gut microbiome patterns that appear to be linked to type 2 diabetes.
As they explain in Nature, the team generated gut microbe metagenomic sequences on fecal samples from 71 Chinese individuals with type 2 diabetes and 74 without. Through the metagenome-wide association study the researchers tracked down hundreds of thousands of gut microbial genes with potential ties to type 2 diabetes — and validation testing in 200 more cases and controls indicated that almost 52,300 of the gene markers were associated with the disease. Among them: markers that showed promise for identifying individuals with type 2 diabetes in the team's follow-up analyses. In addition to some specific metabolic shifts in the type 2 diabetes-associated microbial communities, the study authors noted, these microbiomes also tended to have increased representation by opportunistic pathogens.
"It is important to point out that our discovery demonstrates a correlation," co-author Karsten Kristiansen, a researcher with the University of Copenhagen and BGI-Shenzhen, said in a statement. "The big question now is whether the changes in gut bacteria can affect the development of type 2 diabetes or whether the changes simply reflect that the person is suffering from type 2 diabetes."
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